1. Field of the Invention
The present invention relates generally to the field of load control, and particularly to the controlling and safely stabilizing a load being suspended under an overhead carrier. More specifically, the present invention relates to a system, apparatus, program product, and related methods for gravity stabilizing a suspended load.
2. Description of the Related Art
Modules or portions of the aircraft are assembled at various stages along an assembly floor. When the work in any particular stage is completed, an overhead crane extracts the module and delivers it to the next stage. Because components are being added at each staging area, the center of gravity of the module changes from stage to stage. The module needs to be lifted and transported along its center of gravity. Finding the center of gravity at each staging area can be extremely time-consuming. This directly affects the span of time to move a component via, for example, an overhead crane.
Load bars can be used as an interface between the overhead crane and the component being lifted. Conventional load bars, however, typically rely on turnbuckles to adjust the load bar, to allow the component to be lifted correctly, e.g., horizontal to the ground or in a level orientation. Moves of various components using such conventional load bars, for example, however, could result in the consumption of one hour or more to adjust the load bar and three hours or more to perform the move.
Further, each component staging area generally requires a separate spreader bar assembly to extract the module for each module version. Thus, if a component has, for example, three variants and six predicted lifts during the assembly process, it could potentially take up to eighteen different load bars to perform the required moves using the conventional equipment and methods. The requirement for eighteen load bars, in turn, besides being undesirable due to equipment costs, significantly increases floor space requirements.
Automated systems designed for centering a lifting device and used for extracting low value components such as, for example, mobile homes, etc., were examined, but found to have undesirable limitations. For example, one automated system that was examined utilized a lifting device which provided automated centering utilizing a pendulum or gimbal-type sensor device in conjunction with manual control. Such device, extracted using a single hook assembly, however, required significant deviation in the leveling of the component to be lifted prior to attempting to properly center itself above the component to be lifted. Further, such device did not provide either redundant control systems or a multi-level safety control system, or even adequate automated visual means of indicating an out of tolerance condition.
Recognized therefore by the Applicants is the need for a system, apparatus, program product, and method for safely lifting and stabilizing high-value components or modules such as aircraft modules that can be used universally across different versions having different centers of gravity, and which can, for example, provide accurate load level sensing, redundant control, and multi-level safety features.